WisconsinCRE R2 Companies acquires 1.1-million-square-foot Post Office building in downtown Milwaukee Staff Writer April 2, 2017 Share on Facebook Share on Twitter Share on LinkedIn Share via email R2 Companies, a Chicago-based real estate investment firm, has acquired the 1.1-million-square-foot post office building in Milwaukee. The four-story structure at 341 W. St. Paul Ave. sits on a 9.3-acre riverfront site in downtown Milwaukee. The iconic property has been home to the U.S. Post Office since 1968. The Post Office building has 1,500 feet of frontage on the Menomonee River in downtown Milwaukee. The building will continue to operate as a central mail-sorting facility and retail post office for at least five years.